#include <bits/stdc++.h>
using namespace std;
int a[10];
int main() {
  int x;
  cin >> x;
  int cur = 0;
  while (x) {
    a[++cur] = x % 10;
    x /= 10;
  }
  sort(a + 1, a + 1 + cur);
  int id = 1;
  while (a[id] == 0) {
    id++;
  }
  cout << a[id];
  for (int i = 1; i < id; i++)
    cout << a[i];
  for (int i = id + 1; i <= cur; i++)
    cout << a[i];
    
  return 0;
}